In the last three years I’ve written five articles for Rock&Gem Magazine. Along the way of research and writing I’ve come across the confusing topic of precious and semi-precious gems — just what do those words mean? I recently bought some used gem and mineral books and they shed new light on an old problem. For me, I can now lay the problem to rest by disregarding the two terms altogether. Read on.
Nevada’s precious gem is the Virgin Valley Black Fire Opal. As the Nevada legislature’s website explains it, “Among the many gemstones found in Nevada, the Virgin Valley Black Fire Opal is one of the most beautiful. The Virgin Valley in northern Nevada is the only place in North America where the Black Fire Opal is found in any significant quantity.”
Nevada’s semi-precious gemstone is turquoise. “Sometimes called the “Jewel of the Desert,” Nevada Turquoise is found in many parts of the State.” But is a small, inferior Black Fire Opal more precious than a large turquoise piece, free from all imperfections?
Decades ago, only five stones were recognized as being precious: diamond, ruby, sapphire, emerald, and precious opal. These due to their rarity, beauty, and durability.
It was acknowledged that the terms precious and semi-precious were somewhat arbitrary, in that a poor diamond specimen could be worth a little whereas an outstanding tourmaline could be worth a lot. One authority wrote that it would be well if another term for semi-precious could be introduced and generally used.
Lapidary instructor Eric Shore brings us into today’s era with this observation: “Precious and semi-precious are terms used to differentiate expensive and not so expensive stones; but where is the line drawn between the two? The more modern use of the word ‘Gemstone’ tends to cover all materials that can be cut and polished.”
BTW, I now sponsor the agate page at Mindat.org (external link)